I also happened to this issue. iPhoneSE2 iOS15 beta6 Xcode12 and Xcode13 beta No error detected, just silence.

Note: Stereo Audio Capture sample code. https://developer.apple.com/documentation/avfaudio/avaudiosession/capturing_stereo_audio_from_built-in_microphones This project always will not work unless the language setting of the device is set to English. For iPad, additional patches are required.

It is fixed in iOS15 beta7 !!

I have (possibly) good news. SKTestSession.failTransactionsEnabled has been depreacted since iOS17, but it behaves strangely on iOS17. (lldb) po session.failTransactionsEnabled false (lldb) po session.failTransactionsEnabled = false 0 elements (lldb) po session.failTransactionsEnabled true We may work around this issue by not setting a value for this variable. // before session.failTransactionsEnabled = false // after if #unavailable(iOS 17.0) { session.failTransactionsEnabled = false } In iOS17 we probably need to use simulatedError(forAPI:).